Unraveling the electron dynamics at catalyst/electrode interfaces is critical for the development of design rules to produce efficient photoelectrochemical (PEC) water oxidation. Unlike the majority of photoanodes investigated for PEC water oxidation, the integration of catalysts with CuWO4 electrodes generally result in comparable or worse performance compared to the bared electrode. This is despite the fact that we have shown surface state recombination limits the water oxidation efficiency with CuWO4 electrodes and a catalyst ought to alleviate this reaction. Here we will present results which deepen the understanding of the energetics and electron-transfer processes at the CuWO4/electrocatalyst interface which control the performance of such systems. Ni0.25Fe0.75Oy (denoted as Ni25) was chosen as a model catalyst, and through rigorous comparison of cyclic voltammetry, current transient and electrochemical impedance spectroscopy (EIS) and intensity modulated photocurrent spectroscopy (IMPS) measurements, we have been able to gain a significant insight into the role of the catalyst and the electron-transfer kinetics at the interface on the performance of CuWO4 for PEC water oxidation. Results from preliminary dual-working electrode experiments will also be presented to unambiguously confirm the catalyst potential and source or water oxidation current.

Investigation of CuWO4/electrocatalyst interface for photoelectrochemical water oxidation

2019 Spring National Meeting

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